THE SPAWNING OF PINK SALMON IN THE SYSTEM ABOVE

HOPE - 1955

DEPARTMENT OF FISHERIES, CA NADA

VANCOUVER , B. C. JUNE 20, 1957 THE SPAWNING OF PINK SALMON IN THE FRASER RIVER SYSTEM ABOVE HOPE - 1955

Department of Fisheries, Canada

Vancouver, B. C. June 20, 1957 BOSTON • BAR

FIG. 1. LOCATION MAP THE SPAWNING SPAWNING OF PINK SALMON OF INPINK THETHE FRASER RIVER SYSTEM ABOVE HOPE - 1955

INTRODUCTION During 1955 the Department of Fisheries continued the studies of the pink salmon population in the Fraser River system above Hope. ( See site map figure 1). Historically, the reports of the Commissioner of Fisheries revealed that previous to 1913 large numbers of pink salmon spawned in the upper Fraser River system, particularly in the Thompson, Nicola and Seton Rivers. In 1913, large amounts of rock were dumped into the river immediately above Hell's Gate, which formed an almost impassable barrier to salmon migration. In the ensuing years, pink salmon were virtually absent from the spawning areas above this point. In 1941, 1943 and in 1945, pinks were captured at Hell's Gate incidentally to sockeye in tagging operations of the International Pacific Salmon Fisheries Commission. During 1945, the first fishway at Hell's Gate was completed, and in 1947, between 1000 and 2000 pink salmon were reported spawning in the . In 1949, they were again reported in the Seton-Cayoosh system and also a small number were recorded spawning in the Nicola River, tributary to the Thompson. In addition some evidence of spawning in the Thompson River itself was reported. The latter was considered of particular significance since reports prior to 1913 stated that "millions of pink salmon passed up the Thompson River every other year and spawned on its gravel beaches and in its tributaries 11 • - 2 -

In 1953, a special pink salmon tagging program was carried

out at Hell's Gate by the Department to determine the total

population of this species which migrated above the canyon area

and to locate and assess the numbers spawning in individual areas.

In addition to the Seton-Cayoosh and the Nicola River systems,

both of which supported increased runs of pink salmon over the

cycle year, spawning ground tag recoveries were made in Deadman

River, Bonaparte River, Portage Creek and Anderson Creek. These

constituted the first spawning reports of this species in these

streams for many years. The Thompson River itself was examined

on foot at various points and small numbers of spawned out pinks

were recovered near Deadman River, Spences Bridge, and Big Horn

Lodge. No actual spawning was observed, primarily due to the character of the stream, the inaccessibility of certain areas

and the somewhat opaque coloration of the water. These conditions

made it extremely difficult to detect fish from the bank or from

a boat. The population of pink salmon spawning above Hell's Gate

in 1953 was estimated to be 244,000, of which over 50,000 were estimated to have spawned in the Seton River system. The

rehabilitation in this system had proceeded at a rapid rate, the spawning population of pinks increasing from an estimated

1000 to 2000 in 1947 to over 50,000 three cycles later in 1953. Although a large increase in the size of spawning populations was evident in every known spawning stream, a large disparity

still existed in the calculated estimate and the total number Figure 2 . Fish-wheel. - 3 -

accountable on the various tributaries. It was strongly

suspected that the Thompson River was being utilized to a very

considerable extent by pink salmon. It was decided, therefore, to repeat the tagging program in 1955 and in addition to survey the Thompson River in order to evaluate the role of that river as

a pink salmon producer. To increase the efficiency of the 1955 program two additional techniques were utilized. The first was the installa­

tion of a "Fish-Wheel" immediately above Hope to catch salmon

for tagging ( See photograph figure 2). Use of the "wheel"

reduced the amount of labor required and at the same time enabled

the sampling to be carried out at a more constant effort. The

second involved the use of a helicopter to operate in conjunction

with the ground surveys. Previous experience had proved this machine to be ideally suited for conducting detailed examinations

of spawning areas. During the spawning period a complete aerial

survey of the pink salmon spawning grounds was carried out.

Because of the large area involved and its inaccessibility, it

·would not have been possible to cover it as completely or as quickly by ordinary methods. The helicopter observer was able to locate and map all the spawning areas, and to pass the

information on to the tag recovery crew.

METHODS

(a) Tagging -

The fish-wheel was installed on the right bank of the - 4 -

Fraser River approximately one mile upstream from Hope, near

the C.P.R. station at Haig. In design, the wheel consists of two scoop-like nets or baskets made by stretching 3 1/2inch seine webbing over a framework of five J-shaped steel pipes,

braced horizontally along the length, with a diagonal brace forming a framework for each side of the net. Each basket is ten feet.. deep by ten feet wide and is fastened oppositely to a bearing mounted shaft. At right angles to the nets, two

additional frames carry paddles. This whole structure is mounted on two pairs of pontoons twenty-four feet long, which in turn are secured to shore by steel cables mounted on winches. The wheel is turned by the action of river current on either the paddles or baskets. In operation, the downstream basket schoops up migrating fish from behind and retains them within the net. As the basket rises above water level, the fish drop into a sloping trough attached to the basket, and then they slip gently into a live-box located between one pair of pontoons.

The fish-wheel was assembled and put into operation on September 1, and tagging commenced on September 6, continu­ ing unti 1 October 13. Petersen type tags and colored baffles were applied to the pink salmon and the length, sex, and thair condition were recorded. The baffle color was changed weekly as an aid in determining timing by visual observation.

At the beginning of the season the wheel operated daily from - 5 -

8 a.m. to 5 p.m. Later in the season, it was considered that the pink salmon run was not being adequately sampled and on September 23, fishing commenced on a 24 hour basis. (b) Tag Recovery - Arrangements were made to carry out two aerial recon­ naissances of the spawning streams by helicopter during the period pink salmon were spawning. The first survey, carried out from September 26 to 29, served primarily as a recon­ naissance flight over the Thompson and Nicola River systems in an effort to locate unknown spawning areas. The results from this survey enabled the tag recovery crew to conduct their program with both a minimum of time and effort. The second survey, conducted from October 15 to 17, was a more thorough and complete survey. In addition to examining the Thompson River system, the observer surveyed the , the Fraser River from Lytton to , the Seton River, , Portage Creek, Bridge River, Yalakum River, Nahatlatch River, and the lower Fraser River in the vicinity of Hope. On both surveys the pink salmon spawning areas located were plotted on topographical maps. In addition, spring salmon spawning sites were noted and recorded. The aerial reconnaissances were carried out at an altitude of 200 feet and at a speed of approximately 20 miles per hour. Periodically, the machine was landed on the river Figure 3. B. C. Electric dam near outlet of . - 6 - banks or gravel bars in order to carry out a closer examina­ tion. It was found that the period of day most ideal for observing pink salmon was between 10 a.m. and 3 p.m., the hours of maximum sunlight. The most outstanding feature of these surveys was the fact that this extensive river system was covered in approximately 16 hours flying time.

A more complete ground coverage of the spawning areas was made in 1955 than in 1953. With the aid from aerial observation, a tag recovery crew of three was able to make regular visits to every major pink salmon spawning area in the system. The live pink salmon were enumerated and all the available dead pink salmon were counted and examined for tags.

A counting device was also installed in the ,fishway of the B.C.E. dam at the outlet of Seton Lake (See photograph figure 3). .This device consisted of a picket section with a counting board installed in the stop-log slots at the upstream end of the fishway. All the salmon moving through the fishway during the period October 4 to October 31 were counted and the tagged salmon, distinguished by the various colored baffles, were recorded. It was not practical to count the salmon throughout a 24 hour period, therefore the movement of salmon through tho counting device was confined to the period of daylight. \ \ \ \ \ \ \ \ \

I

4. The daily catch of pink salmon at the fish-wheel site by both the 8 A.M. to 5 P.M. and 24 hour periods. Both curves are based on a 3-day moving average. 120

COMMERCIAL

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12 20 28 5 17 21 25 29 7 11

AUGUST SEPTEMBER OCTOBER Figure A comparison of the daily Area 29 commercial catch with the daily fish-wheel catch at Hope for 1955. The fish-wheel catch has been pre-dated 5 days. - 7 - RESULTS During the period September 6 to October 13, a total of 606 pink salmon were caught and tagged at the fish-wheel site above Hope. Of this number, 381 were caught during the 8 A.M. to 5 P.M. period, while the remaining 225 were caught during the 5 P.M. to 8 A.M. period from September 22 to October 13. The fishing intensity was increased on September 23 because the efficiency of the wheel at this particular site was unknown, and, it was felt that the pink salmon run was not being adequately sampled during the 8 - 5 fishing period. The 24 hour catch is compared with the 9 hour catch in Figure 4. This comparison indicates that, with the exception of a period very late in the season, the twenty-four hour fishing period seems to have only accentuated the 9 hour catch. Late in the season, the water was less turbid and this factor probably accounts for the smaller catches during the daylight period.

The daily catch for the period 8 A .M. to 5 P .M. seems to follow the daily commercial catch in the lower river very closely. (Figure 5.) A significant increase in the daily tagging total occurs five days following each closure of the fishery, and conversely, a sudden decrease in catch occurs five days after each opening of the fishery. These results indicate that the pink salmon populations migrating to the upper spawning areas were sampled proportionately and that the tagged to untagged ratio determined from the spawning ground surveys can be used in calculating a population estimate for the upper area as a whole. - 8 -

Even though a concerted effort was made to sample as many dead as possible, the total sample was much smaller than expected.

A total of 8,178 dead pink salmon were examined and nine tags recovered, Table 1.

TABLE 1. Spawning ground samples and tag recoveries for each stream

-Combined Number of Tags Recovered Stream Female Sample Male Sample Sample Seton River 1300 3 Thompson River 1862 4 Nicola River 2 Portage Creek 6 0 Bonaparte River 28 33 Nahatlatch River 6 11 Anderson Creek 0 1 1

Totals 2139 8178 9

A very small percentage of dead pink salmon "hang up" in the

Thompson River, and consequently the number of dead sampled from this system is very low. Unusual high water conditions in the

Nicola and Seton-Cayoosh systems late in October, coincided with a good recovery period. Consequently, most of the weak and dead fish were swept out of those rivers, lowering the recovery.

These conditions, coupled with a small tagged sample, prevented a high tag recovery. - 9 -

Table 11 lists the total tag recoveries from both above and below the tagging site.

Table 11. Breakdown of tag recoveries above and below tagging site.

8 A.M. - 5 P.M. 5 P.M. - 8 A.M. Combined Spawning streams 9 9 Indian fishery 7 2 9 Commercial fishery 7 2 9 Local residents below tagging site 2 2

Combined

Below tagging site 2 9 11

Above tagging site 16 2 18

Of 18 tags recovered above, only two were from the group tagged during the 5 P.M. to 8 A.M. period, while of the nine tags recover­ ed from below, seven were tagged during that period. The two

8 A .M. to 5 P .M.fish from the latter sample were both tagged on September 24, when only five pink salmon were handled. On that day a photographer was taking pictures of the fish-wheel in operation and the fish caught were used for demonstration, and were undoubtedly weakened by the repeated handling. Fish caught during the 5 P.M. to 8 A.M. period were tagged just once daily, at 8 A .M., and therefore many were held in the live box several hours. The small number of 5 P.M. to 8 A.M. fish recovered above and the relatively large number recovered below indicate that a - 10 -

high percentage mortality occurred in this sample. It was primarily for this reason and the fact that the salmon caught and tagged during the 8 A .M. to 5 P .M. period represented a term of constant fishing effort that only those salmon tagged during this

latter period have been used in calculatin6 the pink salmon population .

Table 1 showed that 9 tags were recovered on the streams from

a total of 381 tagged, in a sample of 8,178 dead salmon. There were seven tags removed by the Indian fishery and these have been

substracted in the calculations from the total number applied.

The population estimate using the Petersen formula was calculated to be 9 x 8178 340,000 salmon. At the 958 confidence level, -

(poisson distribution) the fiducial limits for the nine recoveries would be 4.0 and 17.1. (Ricker, 1937)¹ Therefore the true population can be expected to fall between 179,000 and 765,000 salmon.

A further population estimate was calculated on the basis of the ratio of tagged to untagged salmon moving through the Seton

River fishway. Table 111 shows that 9 tags were observed from the total of 381 fish tagged in a sample of 8805 live salmon. Observa­ tions of the coloured baffles from the nine tagged salmon estab­ lished that iix of them were from the 8 A.M. to 5 P.M. tagging

1 Ricker, W.E.. , 1937. The concept of confidence or .fiducial limits applied to the Poisson frequency distribution. J. Amer. Statistical Assn. 32: 349-356. - 11 -

TABLE 111. Mean migration time between tagging site and Seton dam fishway.

Tags Observed Passing Through Date of Tagging Mean Migration Seton Dam Fishway Time Date Observed; Baffle Colour\ Oct. 5 White Sept. 6-15 24 ii 6 Blue 11 16-22 17 II 8 te fl 27

8 27 10 Red ti 23-29

12 Black JO-Oct. 6 9 13 Black 30-0ct. 6 10 II 13 White " 6-Sept 32 II 13 White 6- 32

Number of tags. . . 9 Total mean migration days ••• 192 Average migration period 21 days period while the remainder could have been tagged during either the 8 A.M. to 5 P.M. or the 5 P.M. to 8 A.M. periods. Because of the high mortality to the fish tagged during the latter period it is possible that all of the tags passing through the fishway were from the 8 A .M. to 5 P .M. sample. If this assumption is accepted then the population estimate calculated from the live to live­ tagged ratio would be = 366,00O salmon. This estimate 374 - 12 -

is only 26,000 higher than that previously calculated from the

spawning stream recovery.

The size of the population has been calculated from a very

small number of tag recoveries and consequently the fiducial limits are quite wide. As with the 1953 calculations, tagging mortality, both immediate and differential, has not been considered.

An increase of 39.3% is shown in 1955 over the 1953 estimate, and assuming that the total percentage mortality was the same for both years, this increase tends to be a real one.

In calculating the timing of the pink salmon migration from

the commercial fishery in the Fraser River to Hope the results

have shown that the daily sampling at the fish-wheel complemented

the commercial catch. The daily catch at the fish-wheel has been moved back five days to compare with the commercial catch. (Figure 5) A very pronounced increase in catch at the tagging site is evident five days following each closure of the fishery and correspondingly, a very sharp decrease in the daily sample follows

each opening of the fishery. A small peak in catch from October 9 to 14, followed by a three day closure, did not show up in the wheel sample, but the fish caught commercially at this time may have been destined for the lower tributary streams. Therefore, from the comparison of the two catches, the migration time from the fishery to Rope appears to be five days.

The Hell's Gate pink salmon tagging program conducted in 1953

included the tagging of fish below the fishways, and the sampling , UNIT EffORT

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AUGt:ST . . Figure 6. A comparison of the daily Area· 29 commercial catch for 1953 with the daily catch per unit of effort of the Hell's Gate tagging crew for the same year. The catch per unit of effort curve has been pre-dated 9 days. - 13 -

of the population above the fishways in order to ascertain a tagged

to untagged ratio. The daily catch and the hours fished were

recorded and from this data a daily catch per unit of effort was

calculated. These results have been compared with the 1953 daily commercial catch and is shown in Figure 6. As with the 1955

comparison of commercial and sampling catch, each closure of the

fishery is followed by an increase in catch while each reopening of

the fishery is followed by a sharp decrease in catch. In this case the migration time appears to be about nine days. One exception is

evident, the ref ore the following comments are included. The closure of September 18 to 24, was not followed by an increase in catch above Hell's Gate, after the expected interval, which would

have been September 27 to October 3. However, between September 26 to 30, the water level dropped to twenty feet on the Hell's Gate gauge, and as a result there was an increase in daily catch below the fishways and a decrease above during that period. The increase in catch per unit effort from 0ctober 1 to 4, following a raise in water levels, very likely represents the group of fish from that closure. These results further demonstrate the possi­ bility of a delay in migration to pink salmon at Hell's Gate when water levels of 22 feet or less are recorded.

In 1953, the 31 tags recovered from the Seton River system were found to have been applied throughout the migration period and in fairly close proportion to the daily tagging totals. These results indicated that the Seton River population of pink salmon formed a II

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Figure 7. A comparison of the daily pink salmon count through the Seton river fishway and the daily fish-wheel catch at Hope. - 14 - daily percentage of the total population passing through Hell's Gate and was not a distinct segment of the population. In Figure 7, the daily pink salmon counts through the Seton fishway are compared with the daily catch at the tagging site. A peak in migration through the fishway occurred on October 9, while the dates of peak migration at Hope occurred between September 16 and 20. This would indicate that the time of migration between Hope and the Seton River would be 19 to 32 days, less an undetermined period of delay required to pass up the river and through the fishway. In addition an average time for migration has been estimated from the nine tags observed passing through the fishway. Table 111 lists the period during which each colour baffle was applied, the mean date of tagging, the date the tags were observed in the Seton River fishways and the calculated time of migration. These results suggest that the average migration time for the tagged salmon is between 18 and 25 days less an undetermined delay at Seton. The pink salmon migrating to the Fraser-Thompson River system were found to be spawning heavily in the main stem of the Thompson

River, between the outlet of Kamloops Lake ~nd Lytton, and in the

Seton River system. There were fairly large numbers of salmon observed spawning in the Nicola River and smaller concentrations were recorded on the Bonaparte River, Deadman River, Anderson

Creek, Stein River and the Nahatlatch River.

The spawning grounds of the Thompson River, both for pink and spring salmon, have been described on a map and are presented in

I \ r SETON CAYOOSH CREEKS POWER DEVELOPMENT PLAN

LOCATION OF SPAWNING GROUNDS 1955 SCALE I inch 800 feet \

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PENSTOCK f

SETON

LEGEND PINK SALMON - Heavy seeding SALMON - seeding

CAYOOSH INTAKE '

:f . 9 15 -

Figure 8. The river has been divided into areas so that in future surveys the spawning grounds will be more easily classified. Major spawning areas carrying substantial numbers of pink salmon were located between the outlet of Kamloops Lake and Shaw Springs.

Further areas, with smaller concentrations of pink salmon, were observed at numerous points along most of the river. In addition, spring salmon were o·bserved spawning in considerable numbers at several points between Kamloops Lake and Spences Bridge. Below

Shaw Springs the physical characteristics of the Thompson River are of the type which would preclude the possibility of the area being utilised by the salmon for spawning. Of the tributaries to the

Thompson River the major spawning areas were found in the Nicola

River. Fairly extensive spawning areas were recorded throughout the lower 16 miles of the stream but the areas were not densely populated with pink salmon. The Bonaparte and Deadman Rivers were both surveyed extensively from the air and on the ground. These streams contained very small numbers of pink salmon.

The pink salmon spawning grounds of the Seton River are shown in Figure 9. Concentrated spawning was observed in the area directly below the dam and in the main river below the confluence of Seton River and Cayoosh Creek. As a result of the intensive aerial and ground surveys conducted throughout the spawning period together with the number of salmon counted through the fishway the population of pink salmon spawning in Seton River was estimated at 75 to 100 thousand. In addition a small number of pink salmon, - 16 - estimated at 500, passed through Seton Lake to spawn in Portage Creek.

Pink salmon, in small numbers, were observed spawning in Bridge River, Stein River, Nahatlatch River and several smaller tributaries or the Fraser River between Bridge River rapiis and Hope. There were no pink salmon observed spawning in the Fraser River above Hope.

Examination of the main stem of the Fraser River above Hope indicated the characteristics of the river would preclude the possibility of this area being suitable for spawning. Below Hope considerable numbers of dead pink salmon were observed on the bars of the river. These fish were examined and in all cases had completed spawning. These results suggested that there could be fairly extensive main stem spawning in the lower Fraser River.

DISCUSSION

Both the tagging and recovery samples for the 1955 pink salmon tagging program were small. However the results indicate that the tagging was carried out in close proportion to the migration. Similar to the 1953 population estimation, no allowance was made for tagging mortality either immediate or differential. The estimate for all pink salmon spawning above Hell's Gate increased from 244,000 in 1953 to 340,000 in 1955, a 39.3% increase. These results are further evidence that the rehabilitation of pink salmon spawning areas above Hell 1 s Gate is proceeding at a good rate. The reasons for the rehabilitation are no doubt associated - 17 - with the somewhat stringent conservation measures applied in recent years in commercial fishing operations on the Fraser and its immediate Canadian approaches and because of the existence of the Hell's Gate fishways since 1945. The use of the fish-wheel in the tagging operation proved satisfactory. The constant fishing effort provided by this device, makes its use ideal in tagging operations of this kind where proportionate sampling is vital. Near the end of the pink salmon migration daylight catches appeared to decline with clearing water conditions and lower water levels. However this occurred after the main section of the run had passed, and could not have seriously affected the results. Tag returns from below the fish-wheel indicated that a high mortality occurred in those fish tagged from

5 P.M. to 8 A.M. Salmon caught during this period were usually held in the live box and tagged once daily at 8 A.M. The mortality to the fish undoubtedly resulted from the practice of holding them in the live box for long periods of time. This mortality was not recorded in the daylight sampling where the salmon were generally tagged within a short time of their capture. These results emphasize the fact that salmon should not be held for extended periods, particularly in tagging operations designed to estimate population size.

Of all streams tributary to the Fraser-Thompson system above

Hope, the Seton River, the Thompson River, between the outlet of

Kamloops Lake and the vicinity of Big Horn Lodge and the Nicola - 18 -

River were found to be the major producers of pink salmon. The

Thompson River is presently supporting a large population of pink salmon and all evidence suggests that it is potentially capable of supporting a much greater population. On the Seton River the intensive aerial and ground surveys c onduc ted throughout the spawn­ ing period together with the number of salmon counted through the fishway indicated that the population of pink salmon spawning in this system was from 75 to 100 thousand. On the Nicola River fairly extensive spawning areas were recorded throughout the lower

16 miles of the stream but the areas were not densely populated with pink salmon. Pink salmon were found in most of the other tributaries of the raser and Thompson Rivers, however they contained very small numbers. There were no pink salmon observed spawning in the main stem of the Fraser River above Hope.

Considerable importance should be attached to the fact that large numbers of dead pink salmon were observed on gravel bars of the

Fraser River below Hope.

The use of a helicopter for surveying the Fraser-Thompson areas was considered to be highly successful. The reconnaissance was particularly valuable in establishin[ the fact that extensive pink salmon spawning areas are located in the main Thompson River.

The tagging program provided information on the approximate timing of the pink salmon migration. The results indicated that the salmon migrated from the commerc ial fishery to Hope in .5 days, from the commercial fishery to Hell Is Gate in 9 days, and from the - 19 - commercial fishery to Seton River in 23 to 30 days.

SUMMARY AND CONCLUSION

During the period September 6 to October 13, pink salmon were caught and tagged in the Fraser River near Rope in order to calculate an estimate of the total population of that species migrating to the up-river spawning areas. An estimate of 340,000

salmon was made which represented a 39.3% increase over the estimate of 244, 000 calculated from a similar program in 1953. The rehabilitation of pink salmon spawning areas above Hope is proceed­

ing at a gratifying rate and justifies the somewhat stringent conservation regulations applied in recent years in commercial fishing operations on the Fraser and its immediate Canadian approaches. Unquestionably, the existence of the Hell's Gate fishways since 1945 has contributed in a major way to this success.

The extensive ground survey, including an aerial reconnaissance by helicopter showed that the major spawning areas are located in the Seton-Cayoosh system, the Nicola River and the main stem of the

Thompson River between the outlet of Kamloops Lake and Lytton. The

Thompson River between the outlet of Kamloops Lake and the vicinity of Big Horn Lodge is presently supporting a large population of pink salmon and all evidence suggests that it is potentially capable of supporting a much greater population.

The "fish-wheel" proved to be satisfactory for the catching and tagging of pink salmon. The device is particularly valuable - 20 -

because there is a constant fishing effort and the personnel

requirements are reduced to a minimum. The number of pink salmon

caught and tagged should have been higher in order to reduce the calculated limits of the population. However, this problem is

receiving further study and it is anticipated that the problem will

be resolved before the commencement of another investigation,

Department of Fisheries, Canada Vancouver, B. C. June 20, 1957.